System for a semiconductor fabrication facility and method for operating the same

ABSTRACT

A system for a semiconductor fabrication facility includes a manufacturing tool including a load port, a maintenance tool including a first track and at least one maintenance crane on the first track, a rectangular zone overlapping with the load port, a plurality of first sensors on the first track and at corners of the rectangular zone configured to detect a location of the maintenance crane and generate a first location date, a transporting tool including a second track and a OHT vehicle on the second track, at least a second sensor on the OHT vehicle and configured to generate a second location data, at least a third sensor on the load port, and a control unit configured to receive the first location data and the second location data, and send signals to the second sensor and the third sensor or to cut off the signal to the second sensor.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.15/636,157, filed on Jun. 28, 2017, entitled of “SYSTEM FOR ASEMICONDUCTOR FABRICATION FACILITY AND METHOD FOR OPERATING THE SAME”,the disclosure of which is hereby incorporated by reference in itsentirety.

BACKGROUND

Integrated circuits are typically manufactured in automated orsemi-automated facilities, by passing substrates/wafers in and on whichthe devices are fabricated through a large number of manufacturing stepsto complete the devices. The number and the type of manufacturing stepsa semiconductor device has to go through may depend on the specifics ofthe semiconductor device to be fabricated. For instance, a sophisticatedchip may require several hundred manufacturing steps.

Furthermore, modern semiconductor fabrication facilities (“FABS”) employsystems to transport workpieces such as substrates/wafers and reticlesto the tools required in the process flow. Therefore reticletransporting devices and wafer transporting devices have been adopted insemiconductor manufacturing tools/apparatuses used in manufacturingprocesses, such as the semiconductor exposure apparatuses used in aphotolithography process. A system that is able to safely andefficiently transfer the workpieces in order to improve the throughputand output rate is thus necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A is a top view of an exemplary apparatus for a semiconductorfabrication facility, in accordance with some embodiments of the presentdisclosure.

FIG. 1B is a side view of the system for the semiconductor fabricationfacility, in accordance with some embodiments of the present disclosure.

FIG. 2 is a block diagram of the system for semiconductor fabricationfacility, in accordance with some embodiments of the present disclosure.

FIG. 3 is a flow chart representing a method for operating the systemfor the semiconductor fabrication facility, in accordance with someembodiments of the present disclosure.

FIG. 4 is a flow chart representing exemplary operations of the methodfor operating the system for the semiconductor fabrication facility, inaccordance with some embodiments of the present disclosure.

FIG. 5A is a top view of an apparatus for the semiconductor fabricationfacility, in accordance with some embodiments of the present disclosure.

FIG. 5B is a side view of the system for the semiconductor fabricationfacility, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

This description of illustrative embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. In the description ofembodiments disclosed herein, any reference to direction or orientationis merely intended for convenience of description and is not intended inany way to limit the scope of the present disclosure. Relative termssuch as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,”“up,” “down,” “top” and “bottom” as well as derivative thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) should be construed torefer to the orientation as then described or as shown in the drawingunder discussion. These relative terms are for convenience ofdescription only and do not require that the apparatus be constructed oroperated in a particular orientation. Terms such as “attached,”“affixed,” “connected” and “interconnected,” refer to a relationshipwherein structures are secured or attached to one another eitherdirectly or indirectly through intervening structures, as well as bothmovable or rigid attachments or relationships, unless expresslydescribed otherwise. Moreover, the features and benefits of thedisclosure are illustrated by reference to the embodiments. Accordingly,the disclosure expressly should not be limited to such embodimentsillustrating some possible non-limiting combination of features that mayexist alone or in other combinations of features; the scope of thedisclosure being defined by the claims appended hereto.

During production, customized parts such as reticles or wafers usuallyare transported from their storage place to manufacturingapparatus/tools and back again by a transporting device in a specific,standardized carrier. When the transporting device is located on andaligned to the manufacturing tool, the carrier is lowered to a load portof the manufacturing tool to load or unload the customized parts.Besides the transporting device, a maintenance device is also requiredin a semiconductor FAB, such that the manufacturing tool(s) can berepaired or maintained in time.

The transporting device and the maintenance device, which areindependent to each other, may be installed in a FAB independently. Forexample, the maintenance tool is suspended from a ceiling of a FAB, andthe transporting device is suspended over the maintenance tool. Moreimportant, the transporting device and the maintenance device areoperated independently. It is found such independent operations for thetransporting device and the maintenance device may cause seriousproblem: When the transporting device is loading or unloading thecustomized parts to or from the load port, it may hit the maintenancedevice in a case that the maintenance device is also moved to above theload port, therefore damages the transporting device. The damagedtransporting device needs to be repaired or replaced, and the repair orreplacement causes unwanted high cost and considerable down time for thesemiconductor FAB.

Present disclosure provides an apparatus and a system for asemiconductor fabrication facility that monitor the locations of themaintenance device and the transporting device to prevent potentialcollision of the two independent devices.

FIG. 1A is a top view of an exemplary apparatus 10 for a semiconductorfabrication facility illustrated with an underlying manufacturing tool100, FIG. 1B is a side view of a system 20 for the semiconductorfabrication facility, and FIG. 2 is an embodiment of a block diagram ofthe system 20 for the semiconductor fabrication facility. Referring toFIG. 1A and FIG. 1B, the apparatus 10 includes a maintenance tool 110and a transporting tool 120. The maintenance tool 110 includes a firsttrack 112 at a first horizontal plane 113, at least one maintenancecrane 114 movably mounted on the first track 112, and a plurality offirst sensors 116 on the first track 112. The transporting tool 120includes a second track 122 at a second horizontal plane 123 differentfrom the first horizontal plane 113, at least one overhead hoistingtransporting (OHT) vehicle 124 movably mounted on the second track 122,and at least one second sensor 126 on the OHT vehicle 124. As shown inFIG. 1A, the first horizontal plane 113 and the second horizontal plane123 partially overlap each other from a plane view. In some embodimentsof the present disclosure, the apparatus 10 can be integrated in asystem 20, as shown in FIG. 1B and FIG. 2, for a semiconductorfabrication facility, and the apparatus 10 integrated in the system 20will be further described according to one or more embodiments in thefollowing description.

In some embodiments, the system 20 can be an automated material handlingsystem (AMHS) automatically handling and transporting customized partsuch as wafer(s) or reticle(s) to manufacturing tools. The AMHS in asemiconductor FAB includes numerous types of automated and manualvehicles for moving and transporting the reticle carriers and/or wafercarriers throughout the FAB during the manufacturing process. This caninclude for example, without limitation, automatic guided vehicles(AGVs), personal guided vehicles (PGVs), rail guided vehicles (RGVs),overhead shuttles (OHSs), and overhead hoist transports (OHTs).

As shown in FIG. 1A, FIG. 1B, and FIG. 2, the system 20 includes atleast a manufacturing tool 100 and the apparatus 10 over themanufacturing tool 100. The apparatus 10 includes the maintenance tool110 over the manufacturing tool 100 and the transporting tool 120 overthe maintenance tool 110. The manufacturing tool 100 can be any type ofwafer handling, fabrication, testing, metrology, or other equipmentcommonly used in a semiconductor FAB. In some embodiments of the presentdisclosure, the manufacturing tool 100 can be, for example but notlimited to, a photolithography tool such as an extreme ultraviolet (EUV)lithography tool. The manufacturing tool 100 includes at least a loadport 102 for inserting or removing a customized part into or from themanufacturing tool 100. In some embodiments of the present disclosure,the load port 102 may include separate loading unit and unloading unit.

The maintenance tool 110 of the apparatus 10 integrated in the system 20includes the first track (including rails) 112 and the maintenance crane114. The first track 112 is affixed and suspended from ceiling 12 of theFAB, and the maintenance crane 114 is movably mounted on the first track112 for maintaining and repairing the manufacturing tool 100.

The transporting tool 120 of the apparatus 10 integrated in the system20 is configured to transport at least one customized part such as awafer or a reticle. For example, the transporting tool 120 transports atleast a reticle when the manufacturing tool 100 is a photolithographytool. The transporting tool 120 includes the second track 122 (includingrails) and the OHT vehicle 124. The second track 122 is affixed andsuspended from the ceiling 12 of the FAB over the first track 112. TheOHT vehicle 124 is movably mounted on the second track 122, and operableto transport the customized part such as the reticle in a carrierthrough the FAB. As shown in FIG. 1A, the OHT vehicle 124 is configuredto complement and cooperate with the second track 122 for rollinglaterally or horizontally along the second track 122 and transportingthe carrier from one location to another. The OHT vehicle 124 over thefirst track 112 is hung up and spaced apart from the first track 112 andthe maintenance crane 114 when horizontally moving along the secondtrack 122. Furthermore, the OHT vehicle 124 is configured and operableto vertically pickup, raise/lower, articulate, and release the carrierto and from the manufacturing tool 100.

Referring to FIG. 1A, FIG. 1B and FIG. 2 again. The apparatus 10integrated in the system 20 includes the first sensors 116 on the firsttrack 112 of the maintenance tool 110. Specifically, the first sensors116 are disposed correspondingly to the load port 102 of themanufacturing tool 100. In some embodiments of the present disclosure,four first sensors 116 are disposed on the first track 112 and onerectangular zone overlapping the entire load port 102 is thereby definedas shown in FIG. 1A. This rectangular zone is referred to as a “dangerzone” 130 because unwanted incident such as collision between twodevices/tools may occur in the zone. The distance between the two firstsensors 116 on the same rail of the first track 112 defines a width 135of the danger zone 130, and the distance between the two first sensors116 on different rails of the first track 112 defines a length 133 ofthe danger zone 130. Accordingly, the length 133 of the danger zone 130substantially equals to the distance between the two rails of the firsttrack 112. More importantly, the width 135 of the danger zone 130 ismade larger than a width of the load port 102, or even larger than awidth of the maintenance crane 114. As shown in FIG. 1A, the width ofthe load port 102 and the width of the maintenance crane 114 aremeasured parallel with the first track 112. Moreover, the first sensors116 are configured to detect a location of the maintenance crane 114. Insome embodiments of the present disclosure, the first sensors 116 mayinclude limit switch or similar mechanically actuated device, but notlimited thereto.

As shown in FIGS. 1B and 2. The apparatus 10 integrated in the system 20includes the second sensor 126 disposed on the OHT vehicle 124 of thetransporting tool 120. And the system 20 includes a third sensor 106disposed on the load port 102 of the manufacturing tool 100. The secondsensor 126 and the third sensor 106 can be a parallel transceiver suchas E84 optical communication sensors, but not limited to this. It isappreciated that the second sensor 126 and the third sensor 106 may beany suitable sensors performing communications therebetween.

Referring to FIG. 2. The system for semiconductor fabrication facility20 further includes a control unit 140 configured to control themaintenance tool 110 and the transporting tool 120 of the apparatus 10.The control unit 140 includes a data collector 142 and an interfacepanel 144. The data collector 142 is configured to collect and storedata from the first sensors 116. For example, the first sensors 116detect the location of the maintenance crane 114 on the first track 112and send data about the location to the data collector 142. Theinterface panel 144 is configured to receive the data from the datacollector 142, and to send signals to the second sensor 126 and thethird sensor 106 or to cut off the signal to the second sensor 126. Insome embodiments of the present disclosure, the system 20 may includemore than one manufacturing tool 100, more than one maintenance crane114, and more than one OHT vehicle 124 as shown in FIG. 2. Accordingly,the control unit 140 can control the maintenance crane 114 and the OHTvehicle individually according to the data received from those sensors116/126, and those details will be further described according to one ormore embodiments in the following description.

Referring to FIGS. 3-4 and with additional reference to FIG. 1A, FIG.1B, and FIG. 2, an exemplary method 30 illustrates one possible flowthrough the system 20 of FIG. 2.

In Operation 300, the first sensors 116 are disposed on the first track112. The plurality of first sensors 116 are located correspondingly tothe load port 102 of the manufacturing tool 100, thus the plurality offirst sensors 116 defines a danger zone 130. As mentioned above, thefirst sensors 116 are disposed on the first track 112 and therectangular danger zone 130 overlapping the entire load port 102 isthereby defined as shown in FIG. 1A.

In Operation 310, location of the maintenance crane 114 is detected bythe first sensors 112 and location of the OHT vehicle 124 is detected bythe second sensor 126. In some embodiments of the present disclosure,Operation 310 may further include Operations 312-316 as shown in FIG. 4.In Operation 312, the location of the maintenance crane 114 is detectedby the first sensors 116 disposed on the first track 112. Referring toFIG. 1A again, the maintenance crane 114 may be located in a waitingarea and may enter the working area in the semiconductor FAB ifrequired. Therefore the first sensors 116 are to detect the location ofthe maintenance crane 114 and generate data about the location of themaintenance crane 114.

In Operation 314, the data is then collected and stored in the datacollector 142 of the control unit 140 through an Ethernet network orother compatible network system. In Operation 316, the collected dataare then transferred to the interface panel 144 of the control unit 140.By receiving the data about the locations of the maintenance crane 114,and by detecting the location of the OHT vehicle 124, the interfacepanel 144 is triggered to switch the load port 102 between two modes: afirst mode such as an automatic mode and a second mode such as a manualmode.

Referring back to FIG. 3, in Operation 320, when the OHT vehicle 124enters the danger zone 130, the interface panel 144 switches the loadport 102 to the first mode, then Operation 322 to Operation 326 aresequentially operated. In Operation 322, the maintenance crane 114 isprohibited from entering the danger zone 130 while the OHT vehicle 124in the danger zone 130 is allowed aligning to the load port 102. InOperation 324, signals are sent from the interface panel 144 of thecontrol unit 140 to both of the second sensor 126 on the OHT vehicle 124and the third sensor 106 on the load port 102 of the manufacturing tool100. In some embodiments of the present disclosure, Operation 322 andOperation 324 may be operated simultaneously.

In Operation 326, a handshaking function is performed by the secondsensor 126 and the third sensor 106 to permit a load operation or anunload operation when the OHT vehicle 124 aligns to the load port 102.In other words, when the second sensor 126 and the third sensor 106receive the signal from the interface panel 144 of the control unit 140,the second sensor 126 and the third sensor 106 communicate and performthe handshaking function, and alignment between the OHT vehicle 124 andthe load port 102 is confirmed, then the load operation or the unloadoperation, which are to vertically lower and release the reticle carrierto the manufacturing tool 100 or to pickup and raise the reticle carrierfrom the manufacturing tool 100, is permitted.

On the other hand, in Operation 330, when the maintenance crane 114enters the working area, especially enters the danger zone 130, theinterface panel 144 switches the load port 102 to the second mode, andthen Operation 332 to Operation 334 are sequentially operated.

In Operation 332, signal sent from the control unit 140 to the secondsensor 126 on the OHT vehicle 124 is cut off to disable the OHT vehicle124. In Operation 334, since the signal to the OHT vehicles 124 is cutoff, the handshaking function between the second sensor 126 and thethird sensor 106 is interrupted, thus the load operation or the unloadoperation is prohibited. In some embodiments of the present disclosure,operations or movements of the OHT vehicle 124 is prohibited such thatthe OHT vehicle 124 will not hit the maintenance crane 114 entering thedanger zone 130. Accordingly, damages to the OHT vehicle 124 due to theimpact/hit are avoided. In some embodiments of the present disclosure,interruption to the handshaking function between the second sensor 126and the third sensor 106 can be achieved by cutting off the signal sentfrom the control unit 140 to the third sensor 106 on the load port 102.In those embodiments, the OHT vehicle 124 can be disabled and theload/unload operations are prohibited after the handshaking function isinterrupted.

In some embodiments of the present disclosure, the second mode is amanual mode. And in the manual mode, the OHT vehicle 124 can be operatedmanually until the maintenance crane 114 leaves the danger zone 130 ormoves back the waiting area.

FIG. 5A is a top view of an apparatus 10′ illustrated with an underlyingmanufacturing tool 100 a, 100 b, and 100 c in accordance with someembodiments of the present disclosure, and FIG. 5B is a side view of aportion of the system for the semiconductor fabrication facility 20′ andthe apparatus 10′ in accordance with some embodiments of the presentdisclosure. In some embodiments of the present disclosure, the systemfor the semiconductor fabrication facilities 20′ includes a plurality ofmanufacturing tools 100 a, 100 b, and 100 c for one manufacturingoperation or different manufacturing operations as shown in FIGS. 5A-5B,and the transporting tool 120 of the apparatus 10′ integrated in thesystem 20′ may include a plurality of OHT vehicles 124 a, 124 b, and 124c using second tracks 122 or rails operable to guide the movement. It isappreciated that the method 30 of FIGS. 3-4 can be applied to the systemfor the semiconductor fabrication facility 20′ of FIGS. 5A-5B. Forexample, in Operation 300, several first sensors 116 are disposed on thefirst track 112 to define a plurality of danger zones 130 a, 130 b, and130 c, and each of the danger zones 130 a, 130 b, and 130 c is definedcorrespondingly to load ports 102 a-102 c of the manufacturing tools 100a-100 c, respectively. In Operation 310, locations of the OHT vehicles124 a-124 c are respectively detected by the second sensors 126, andlocations of the maintenance cranes 114 a and 114 b are respectivelydetected by the first sensors 106. Thus, the interface panel 144 of thecontrol unit 140 switches the load port 102 a-102 c between the firstmode and the second mode individually according to the locationdetection result of the OHT vehicles 124 a-124 c and the maintenancecranes 114 a-114 b.

For example in some embodiments of the present disclosure, when the OHTvehicle 124 c enters the danger zone 130 c while the OHT vehicles 124 aand 124 b are out of the danger zones 130 a and 130 b, the interfacepanel 144 of the control unit 140 switches the load port 102 c to thefirst mode or the automatic mode as in Operation 320. Accordingly, themaintenance cranes 114 a and 114 b are prohibited from entering thedanger zone 130 c, for example, maintenance cranes 114 a and 114 b canno longer be automatically controlled. In some embodiments, themaintenance cranes 114 a and 114 b are switched to manual control oncethe load port 102 c is in the automatic mode. However, the maintenancecranes 114 a and 114 b can be manually controlled to enter the dangerzones 130 a and 130 b without any OHT vehicle occupying, if required.

On the other hand, when the maintenance crane 114 b enters, for example,the danger zone 130 a, the interface panel 144 switches the load port102 a to the second mode as in Operation 330. In some embodiments of thepresent disclosure, the OHT vehicle 124 a is not in the danger zone 130a when the maintenance crane 114 b entering the danger zone 130 abecause the maintenance crane 114 b would have been prohibited fromapproaching danger zone 130 a if the second sensor 126 a identifies theOHT vehicle 124 a was already in the danger zone 130 a.

In some embodiments of the present disclosure, when the OHT vehicle 124a is already in the danger zone 130 a and the maintenance crane 114 bmistakenly and accidentally enters the danger zone 130 a as shown inFIGS. 5A and 5B, the interface panel 144 switches the load port 102 a tothe second mode according to the location detection result. Thus, theOHT vehicle 124 a in the danger zone 130 a is disabled by cutting offthe signal from the control unit 140 to the second sensor 126 on the OHTvehicle 124 a. Consequently, the handshaking function between the secondsensor 126 on the OHT vehicle 124 a and the third sensor 106 on the loadport 102 a is interrupted, and the load or unload operation isprohibited. In some embodiments, since the second mode for the load port102 a is a manual mode, the disabled OHT vehicle 124 a cannotautomatically controlled and is remained at its position at the time theload port 102 a being switched to the manual mode as shown in FIG. 5B.Since the load operation or the unload operation is prohibited, impactbetween the OHT vehicle 124 a and the maintenance crane 114 b isavoided. Away from the danger zone 130 a, if the OHT vehicles 124 b and124 c are in the danger zones 130 b and 130 c, the load port 102 b and102 c are still in the first mode, and the maintenance cranes 114 a and114 b are still prohibited from entering the danger zone 130 b and 130c. In other words, if the OHT vehicles 124 b and 124 c are not in thedanger zones 130 b and 130 c, the maintenance cranes 114 a and 114 b arefree to enter danger zones 130 b and 130 c.

It will be appreciated that in the forgoing method, the maintenancecrane is prohibited entering the danger zone when the OHT vehicle is inthe danger zone, therefore hit or impact between the OHT vehicle inoperation and the maintenance crane is avoided. And when the maintenancecrane enters the danger zone, the OHT vehicles are disabled and noload/unload operation is permitted, therefore hit or impact between theOHT vehicle and the maintenance crane in operation is also avoided.

It will be further appreciated that the foregoing apparatus and systemmay be used in the automated material handling system (AMHS) forsemiconductor fabrication facilities. Accordingly, the manufacturingtool is not limited to the EUV photolithography along, and the OHTvehicle is not limited to transport the reticle(s) along, either. TheOHT vehicle may be appropriately configured to accommodate any type ofcustomized by those skilled in the art without undue experimentation.

According to one embodiment of the present disclosure, a system for asemiconductor fabrication facility is provided. The system includes amanufacturing tool including a load port, a maintenance tool over themanufacturing tool, a rectangular zone overlapping with the load port ofthe manufacturing tool, a plurality of first sensors, a transportingtool between the maintenance tool and the manufacturing tool from a sideview, at least a second sensor, at least a third sensor, and a controlunit. The maintenance tool includes a first track and at least onemaintenance crane movable mounted on the first track. The plurality offirst sensors are disposed on the first track and at corners of therectangular zone. The first sensors are configured to detect a locationof the maintenance crane and generate a first location data. Thetransporting tool includes a second track and at least one OHT vehiclemovably mounted on the second track. The second sensor is disposed onthe OHT vehicle and configured to generate a second location data of theOHT vehicle. The third sensor is disposed on the load port. The controlunit is configured to receive the first location data of the maintenancecrane and the second location data of the OHT vehicle, and send signalsto the second sensor and the third sensor or to cut off the signal tothe second sensor.

According to another embodiment, a method for operating a system for asemiconductor fabrication facility is provided. The method includesfollowing operations. A manufacturing tool, a maintenance tool, atransporting tool and a control unit are provided. The manufacturingtool includes a load port. The maintenance tool includes a maintenancecrane. The transporting tool includes an OHT vehicle. The control unitincludes a data collector and an interface panel. A danger zoneoverlapping the load port of the manufacturing tool is defined. Alocation of the maintenance crane of the maintenance tool is detectedand a first location data of the maintenance crane is generated. Alocation of the OHT vehicle is detected and a second location data ofthe OHT vehicle is generated. Switching, by the control unit, between afirst mode when the second location data overlaps with the danger zoneand a second mode when the first location data overlaps with the dangerzone.

According to one embodiment of the present disclosure, a method foroperating a system for a semiconductor fabrication facility is provided.The method includes following operations. A manufacturing tool, amaintenance tool, a transporting tool and a control unit are provided.The manufacturing tool includes a load port. The maintenance toolincludes a maintenance crane. The transporting tool includes an OHTvehicle. A danger zone overlapping the load port is defined. A locationof the maintenance crane of the maintenance tool is detected. A locationof the OHT vehicle is detected. The maintenance crane is prohibited fromentering the danger zone when the OHT vehicle enters the danger zone.The OHT vehicle is disabled when the maintenance crane enters the dangerzone.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A system for a semiconductor fabrication facility, comprising: a manufacturing tool comprising a load port; a maintenance tool over the manufacturing tool, wherein the maintenance tool comprises a first track and at least one maintenance crane movably mounted on the first track; a rectangular zone overlapping with the load port of the manufacturing tool; a plurality of first sensors on the first track and at corners of the rectangular zone, wherein the first sensors are configured to detect a location of the maintenance crane and generate a first location data; a transporting tool between the maintenance tool and the manufacturing tool from a side view, wherein the transporting tool comprises a second track and at least one overhead hoisting transporting (OHT) vehicle movably mounted on the second track; at least one second sensor on the OHT vehicle configured to generate a second location data of the OHT vehicle; at least one third sensor on the load port; and a control unit configured to receive the first location data of the maintenance crane and the second location data of the OHT vehicle, and send signals to the second sensor and the third sensor or to cut off the signal to the second sensor.
 2. The system of claim 1, wherein a width of the rectangular zone is greater than a width of the load port.
 3. The system of claim 1, wherein the control unit comprises: a data collector configured to collect the first location data from the first sensors; and an interface panel configured to receive the first location data from the data collector and send signals to the second sensor and the third sensor or to cut off the signal to the second sensor.
 4. The system of claim 1, wherein the second sensor and the third sensor perform a handshaking function to permit a load operation or an unload operation when the OHT vehicle enters the rectangular zone and aligns to the load port.
 5. The system of claim 4, wherein the maintenance crane is prohibited from entering the rectangular zone when performing load operation or the unload operation.
 6. The system of claim 1, wherein the control unit cuts off the signal to the second sensor when the maintenance crane enters the rectangular zone.
 7. The system of claim 6, wherein when the signal to the second sensor is cut off, a handshaking function between the second sensor and the third sensor is interrupted, and a load operation or an unload operation is prohibited.
 8. A method for operating a system for a semiconductor fabrication facility, comprising: providing a manufacturing tool comprising a load port, a maintenance tool comprising a maintenance crane, a transporting tool comprising an OHT vehicle and a control unit comprising a data collector and an interface panel; defining a danger zone overlapping the load port of the manufacturing tool; detecting a location of a maintenance crane of the maintenance tool and generating a first location data of the maintenance crane; detecting a location of the OHT vehicle and generating a second location data of the OHT vehicle; and switching, by the control unit, between a first mode when the second location data overlaps with the danger zone and a second mode when the first location data overlaps with the danger zone.
 9. The method of claim 8, further comprising collecting the first location data by the data collector of the control unit.
 10. The method of claim 8, further comprising switching between the first mode and the second mode by the interface panel of the control unit.
 11. The method of claim 8, further comprising prohibiting the maintenance crane from entering the danger zone when the control unit switches to the first mode.
 12. The method of claim 11, further comprising allowing the OHT vehicle aligning to the load port in the first mode.
 13. The method of claim 12, further comprising sending signals to the second sensor and a third sensor on the load port in the first mode.
 14. The method of claim 13, further comprising performing a handshaking function, by the second sensor and the third sensor, to permit a load operation or an unload operation when the OHT vehicle is aligned to the load port.
 15. The method of claim 8, further comprising cutting off the signal to the second sensor to disable the OHT vehicle in the second mode.
 16. The method of claim 15, further comprising interrupting a handshaking function between the second sensor and a third sensor on the load port to prohibit a load operation or an unload operation in the second mode. 